This study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as fragmented aurora-like emission(s) (FAEs). An all-sky camera captured these FAEs on three separate occasions in 2015 and 2017 at the Kjell Henriksen Observatory near the arctic town of Longyearbyen, Svalbard, Norway. A total of 305 FAE candidates were identified. They seem to appear in two categories – randomly occurring individual FAEs and wave-like structures with regular spacing between FAEs alongside auroral arcs. FAEs show horizontal sizes typically below 20 km, a lack of field-aligned emission extent, and short lifetimes of less than a minute. Emissions were observed at the 557.7 nm line of atomic oxygen and at 673.0 nm (N₂; first positive band system) but not at the 427.8 nm emission of ${\mathrm{N}}_{\mathrm{2}}^{+}$ or the 777.4 nm line of atomic oxygen. This suggests an upper limit to the energy that can be produced by the generating mechanism. Their lack of field-aligned extent indicates a different generation mechanism than for aurorae, which are caused by particle precipitation. Instead, these FAEs could be the result of excitation by thermal ionospheric electrons. FAE observations are seemingly accompanied by elevated electron temperatures between 110–120 km and increased ion temperatures at F-region altitudes. One possible explanation for this is Farley–Buneman instabilities of strong local currents. In the present study, we provide an overview of the observations and discuss their characteristics and potential generation mechanisms.

中文翻译：

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在斯瓦尔巴特群岛上观测到的极光样碎片（FAE）碎片的特征

这项研究分析了一种新型的小规模极光状特征的观测，这种特征还被称为碎片化极光状发射（FAE）。2015年和2017年，全天候相机分别在挪威斯瓦尔巴特群岛北极镇朗伊尔城附近的凯耶尔·亨里克森天文台分三次捕获了这些FAE。总共确定了305名FAE候选人。它们似乎分为两类-随机发生的单个FAE和波浪形结构，FAE与极光弧之间具有规则的间距。FAE的水平尺寸通常小于20 km，缺乏场校准的发射范围，寿命短于一分钟。在557.7 nm原子氧谱线和673.0 nm（N ₂; 第一个正带系统），但在427.8 nm处没有发射${\mathrm{ñ}}_{\mathrm{2个}}^{+}$或原子氧的777.4 nm线。这暗示了可以由发电机构产生的能量的上限。它们缺乏场对准的范围，这表明与产生极光的机制不同，这是由粒子沉淀引起的。相反，这些FAE可能是热电离层电子激发的结果。FAE观测似乎伴随着110-120 km之间的电子温度升高和F区高度的离子温度升高。对此的一种可能解释是强当地潮流的Farley-Buneman不稳定性。在本研究中，我们提供了观测的概述，并讨论了它们的特征和潜在的生成机制。